bright red snake in Costa Rica's Tortuguero Canals

Can anyone id a bright red snake I saw in Costa Rica? It was twined around the end of a branch of a tree that was on the edge of one of the Tortuguero Canals. No markings, only bright red all over-top and bottom, thin, maybe about 2 feet long. The guide said I was imagining it!? Me, my video recorder, AND another guy, huh?! Thanks.